.nav{
    width:100%;
    height:40px;
    display: flex;
    font-size: 20px;
    li{
       height:100%;
       width:40px; 
       display: flex;
       justify-content: center;
       align-items: center;
       &:nth-child(2){
           display: flex;
           flex: 1;
       }
    }
}